The record source in a report is read only. If you want to update totals in the table you will have to open the record and write back to it. I'd be inclined to do this with a sql update. I also have a domain write function that I could give you if you want it.
If you want to store your totals to an array you'll have to dim your array before the report runs, in the declarations section, perhaps in the OnOpen event, then write to it with each total, in other words in the Print event of where ever the total is. Don't forget to process the array before the report closes or you'll lose it. Alternatively you could dim the array in a database module as opposed to the report module. You should be able to find information on working with arrays in Access help.